Hi Paul, > > it looks to me that the ISO C and ISO C++ committees need to > > do some more work to align the syntaxes. > > This is pretty unlikely. They won't converge here, > just as they didn't converge with 'bool'.
Huh? 'bool' is usable the same way in C and C++, with only minor semantic differences. But with 'noreturn', programmers need to write extern #ifdef __cplusplus [[noreturn]] #else noreturn #endif void foo (int); > The _Noreturn / <stdnoreturn.h> part of draft C1X has been present > in multiple drafts; I think it's reasonably safe to start tracking > it at this point. I'm still not so sure. _Noreturn has been there for some time, yes. But <stdnoreturn.h> and 'noreturn' have been introduced after n1548.pdf (dated 2010-12-02). And also on the C++ side, there seem to have been discussions around the use of the brackets less than a year ago. In the current state, <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3288.htm> implies that defining 'noreturn' as a macro will be invalid in C++. But that's exactly what ISO C <stdnoreturn.h> does. Therefore IMO in the gnulib module description for this module we must clearly mention that this header file cannot be used in C++. > My patch prefers _Noreturn when it can, for two reasons: > > * In contexts like lib/stdlib.in.h, it reduces namespace pollution. > > * It removes a dependency on the stdnoreturn module. Good. And it also avoids problems with C++ and with MS compilers. > if these files (namely, openat.h, > sigpipe-die.h, xalloc.h, xmemdup0.h, xstrtol.h) are not intended > to be copied elsewhere, it'd be better to be consistent and to > have them use _Noreturn as well; that way, their modules wouldn't > need to depend on the stdnoreturn module. Generally, all gnulib header files that are meant to be possibly copied elsewhere use "#if @HAVE_...@" instead of "#if HAVE_...", and have mechanics to incorporate the contents of build-aux/arg-nonnull.h, build-aux/c++defs.h, build-aux/unused-parameter.h, build-aux/warn-on-use.h, as needed. For this reason, they are all called *.in.h. openat.h, sigpipe-die.h, xalloc.h, xmemdup0.h, xstrtol.h are all meant to reside only in a source tree of a package that uses gnulib. They can rely on _Noreturn directly (from gnulib-common.m4). I would prefer if these files could use '_Noreturn' as well, for consistency, and to avoid problems in mixed C / C++ packages (such as gettext and Octave). Bruno -- In memoriam Zahra Kazemi <http://en.wikipedia.org/wiki/Zahra_Kazemi>
